A quantum network node with parabolic mirror and pre-aligned optics

Remote entanglement of two quantum processors or quantum sensors enables wide range of applications including distributed quantum computing, enhanced sensing, and secure communication. In particular, a network of quantum computers can solve one of the major challenges in the field which is scaling to build a large enough quantum processor. However, building such a network is challenging and requires generation of entanglement at a fast rate. One of the main bottlenecks in increasing the entanglement rate is photon collection efficiency.



Here, we report on our progress towards remote entanglement of two rubidium atoms which form the building block of the quantum network. In order to increase the entanglement rate, we use a parabolic mirror to collect the scattered photons. The collected photons are coupled into a single-mode fiber inside the vacuum chamber which also carries the dipole trap light. Therefore, the photon collection efficiency is insensitive to slight misalignment of the optics. Moreover, we have built the core of the setup on a chip by using millimeter-size optics. With the pre-aligned optics on the chip and fiber-coupled out of the vacuum chamber, the assembly can function as a plug-and-play quantum network node.